Lake Mattamuskeet: Using the Past to Help Determine the Future
Recent research conducted by UNC Coastal Studies Institute scientists suggests a rare ecological phenomenon exists in Lake Mattamuskeet, North Carolina’s largest natural lake. Located in Hyde County, the physical structure and history of Lake Mattamuskeet intrigued scientists to study what appears to be two unique habitats coexisting side by side. Scientists from the UNC Coastal Studies Institute and UNC Chapel Hill are examining the history of the lake, its formation, and historical change in plant and algal life in order to better understand how the ecosystem functions.
Lake Mattamuskeet has a long history of varied uses and multiple personalities. The lake has seen many changes since its discovery by early English settlers in the mid 1500’s. Efforts to drain the lake for farming began as early as 1825 with the creation of the first canal connecting the lake to nearby Wysocking Bay in the western Pamlico Sound. The historic Lake Mattamuskeet lodge began its life as a pumping station, keeping the lake bed dry for farming beginning in 1915. By 1932 pumping ceased due to increasing costs, and the lake was allowed to refill once again. By 1942, U.S. 94 was completed across the lake. This highway divides Mattamuskeet into two sides, east and west. Culverts through the road provide water flow between sides, allowing the exchange of both suspended sediment and nutrients.
Not only does Lake Mattamuskeet have an interesting past, UNC CSI scientists have discovered that the lake is presently an unusual ecological phenomenon. “The lake is plant-dominated on the East side and algae dominated on the West” said Dr. Michael Piehler, lead investigator on the project at Lake Mattamuskeet, “to have two different stable states in one lake is a very rare occurrence, it just does not happen”. UNC CSI Scientists believe that this lake is unique and know of no other natural lake in the country that exhibit two distinct stable states.
Dr. Piehler and UNC Graduate Student and UNC-CSI Research Fellow Matt Waters are trying to determine how these ecosystems may have formed by studying the history of past primary producer communities. They are also interested in whether or not one habitat could give way to another. “There is potential for a switch there,” states Piehler, “we will run a suite of experiments to determine if anything has or could drive a shift in states. “ UNC CSI scientists and partners are doing this by collecting both short and long sediment cores and conducting nutrient addition bioassays.
Matt Waters is reconstructing Lake Mattamuskeet’s primary producer history by taking cores of the lake bottom sediment with a piston push core. One meter cores taken at depositional areas on the east and west sides of the lake and are used to determine the distribution of nutrients, photosynthetic pigments and organic matter. Photosynthetic pigments (chlorophyll-a, beta-carotene, etc.) are a direct measurement of primary producer communities and can be used to determine past algal groups and plant abundance on the two sides of the lake. Waters states, “The principal objective of rebuilding the lake’s primary producer history is to determine when the dual stable states began which can then identify past management practices that may have caused them, and how those conditions may benefit the lake.”
In addition to the short cores, UNC-CSI partnered with Dr. Antonio Rodriguez of UNC Chapel Hill’s Institute of Marine Science and performed two long cores of four meters in length using a vibracore system. Data gained from these long cores will be used to validate the findings of the short cores, gain perspective on the potential origin of the lake, and characterize past ecosystem status.
Lake water nutrient addition bioassays performed by Dr. Piehler are intended to test how each side of the lake would respond to nutrients inputs. Material collected from each side of the lake was tested for response to nitrogen, phosphorus and a combination of the two. Dr. Piehler says these tests help us understand how the lake may switch from one state to another. "Using nutrient addition bioassays we can improve our understanding of the nutrient-phytoplankton relationships, which may help us determine the effects of potential land use changes in the lake’s watershed." states Piehler.
The results of these experiments will provide us with information not only on the fascinating history of lake formation and its ecosystems, but how changes in plant and algal communities might be linked to the history of past land uses and their practices. Importantly, this information can be applied to assist land use managers as to what practices may help preserve the health of this fragile ecosystem so it can be a valuable natural resource for future generations.